Tool-chuck.



J. S. PRAY. TOOL CHUCK. APPLICATION FILED 001'. 20, 1909.

957,760, Patented May 10, 1910.

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Patented May 10, 1910.

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JOHN S. FRAY, 0F BRIDGEPORT, CONNECTICUT, ASSIGNOR TO THE JOHN S. FRAY COM- PANY, OF BRIDGEPOBT, CONNECTICUT, A CORPORATION OF CONNECTICUT.

TOOL-CHUCK.

Specification of Letters Patent.

Patented May 10, 1910.

To all whom it may concern:

Be it known that 1, JOHN S. FRAY, a citizen of the United States, residing at Bridgeport, county of Fairfield, State of Connecticut, have invented certain new and useful Improvements in Tool-Chucks, of which the following is a full, clear, and exact description.

This invention relates to improvements in tool-holding chucks, and is particularly useful in connection with hand tools such as bit-braces.

The object of the present invention is to provide a simple, yet powerful, chuck construction by which bits and drills of a wide range of sizes, and whether provided with a square or round shank, may be held with great security. To accomplish the results aimed at, I provide improvements in the chuck jaws. Many efforts have been made to construct jaws which will hold boring tools, whether provided with round or square shanks, and to so construct the chuck that boring tools of a wide range of sizes may also be employed, but such efforts have been attended in the past with very meager and unsatisfactory results. By my improve ments the smallest drill (such as employed with this kind of a tool) may be securely held. So also may a drill of approximately one-half inch diameter be securely held, that range of sizes including all drills such as are practical for use in a hand-driven instrument.

In the accompanying drawings, Figure 1 is a side elevation of my invention as applied to a bit-brace, a portion of the latter only being shown. Fig. 2 is a side elevation of a detached detail. Fig. 3 is a longitudinal sectional view of the chuck as shown in Fig. 1. Fig. 4 is a side elevation of certain details shown in Fig. 3, said parts being detached and in a different position from that shown in said figure. Fig. 5 is an edge view of the parts shown in Fig. 4. Fig. 6 is a section on the line mw, Fig. 1, certain parts being shown in elevation. Fig. 7 is a section of a detail detached. Fig. 8 is an elevation of the lower end of the part shown in Fig. 2. Fig. 9 is a side elevation of Fig. 5, certain parts being shown in section on the line yy of said figure. Fig. 10 is a section on the line z-2 Fig. 9 relatively en larged. Fig. 11 is an end view of the chuck.

The main frame or body of the chuck is shown in Fig. 2, and includes a head 1, hav- 111g an opening at the forward end for the introduction of a boring tool. This opening is angular in outline to receive the chuck jaws 22 and to prevent the same from turning independently of the head. The frame 1 is also slotted longitudinally, as at 1*. In this slot is located what I term the jaw driver 3, the edges of said driver being threaded and projecting slightly through the slot to be engaged by the jaw-operating device later described.

t is a threaded bearing near the rear end of the frame. 5 is the driving end of said frame. It is immaterial what sort of driving mechanism is employed, but in the form shown in the drawings the chuck is applicable for use with a bit-brace, a portion of the bit-brace being indicated at 6, said bitbrace being of the ratchet type, (S being one of the ratchets, the same being arranged to engage with pawl teeth on the driving end 5 of the frame.

7 is an internally threaded jaw-operating sleeve mounted to rotate upon the main body around the slotted portion thereof, the forward end of said sleeve bearing against a shoulder at the rear of the head, the rear end being supported by an anti-friction bearing. This anti-friction bearing includes the balls 9 located in a race-way in the collar 8, mounted to turn upon the threaded portion 1 of the frame. It also preferably includes a hardened bearing washer 10, interposed between the rear of the sleeve 7 and the balls 9. The ball-race and the collar 9 may be hardened to resist wear. A suitable portion of the bore of the sleeve 7 is threaded to cooperate with the threads on the outer ends of the jaw driver block 3.

Then the parts are assembled it will be observed that rotation of the sleeve 7 will cause the jaw driver block 3 to move to and fro. The front end of the jaw driver block is recessed, the opposite walls of said recess flaring outwardly to afford a tapered seat for the heels of the jaws 22 Said seat is indicated at 15. The jaws are loosely connected to the block 3 by a link 12, which may be formed of wire, which link may have an eye at one end to surround the intermediate portion of a bowed spring 11, by which the jaws 2-2 may normally be forced apart. Vvithin the head 1 of the frame, the bearing walls for the jaws 22 are tapered, as at 14:, the ends of the jaws being correspondingly tapered, as at 13. The inner face of each jaw 2-2 is provided with what I will term a main longi tudinal groove, while both jaws are preferably provided with alternately registering teeth 1515. The main grooves are as shown of V-shaped cross section and are deepest at a point of approximately onethird of the way back from the outer ends of said jaws, the function of said longitudinal grooves so deepened being to receive and grip the usual enlarged pyramidal shank of a boring bit. The corners formed by the main grooves are provided, to the rear of the deepest part of the main grooves, with what I will term supplemental excavations indicated at 16-46, the function of said supplemental excavations being twofold, viz., to afford clearance for the round shank of a drill (as distinguished from a bit) and to very effectively grip such round shank, particularly in the larger sizes. By

providing these supplemental excavations drills of the large sizes may be inserted sufficiently far into the jaws so as to be effectively supported against deflection. lVere it not for the supplemental excavations at the corners formed by the main grooves, it would not be possible to insert the large size drills sufliciently far to enable them to be properly supported against the side strain to which all such tools are bound to be subjected. Furthermore, it will be apparent that by forming these supplemental excavations each jaw is so constructed that it may grip certain size drills (the larger sizes) at four points in the circumference of the shank instead of two points, whereby such larger drills are held with such a secure grip that they will not turn in the chuck. As shown, the supplemental excavations are extended from about over the deepest part of the main grooves to a point approximately midway in the length of each aw, although obviously they could be extended farther if desirable, the purpose of extending each supplemental excavation to the point shown being to substantially equalize the leverage at each end of each jaw, so that each jaw will readily tilt into a position to grip the round shank of a tool for a considerable length.

In Fig. 9 I have illustrated approximately the position of the jaws in the act of holding a large drill, the position of the drill being indicated in dotted lines (see also Fig. 10). The supplemental excavations afford clearance for the rear end of the round shank of the drill, so that the jaws can be advanced to a point where they will clamp down effectively on the surface of the drill, well forward of the rear end thereof.

I have found that a comparatively small supplemental excavation very greatly increases the range'of usefulness of the chuck.

I am, of course, aware that many chuck jaws have been constructed with hollowed out recesses to afford clearance for boring tools having so-called pyramidal shanks, but such chucks are not applicable for the successful holding of boring tools such as drills having round shanks, since in the gripping of such tools it is necessary to hold the same throughout a substantial portion of their length, whereas jaws of the type I have referred to only grip round shanked tools at one point. The contact faces of the jaws in the present instance are so arranged as to contact throughout their entire length, or substantially so, thus permitting the tool to be successfully employed with either of the types of boring tools referred to herein.

By the arrangement shown, since the heels of the jaws are not rigidly hinged, it is possible for the same to expand and contract so that each jaw may have a swinging or tilting movement whereby it may adjust itself precisely to the shape of the shank in such a manner as to grip the latter for a substantial portion of its length, thus preventing the boring tool from tilting. In this respect it will be observed that the in clines 14: within the head 1 and the inclines of the recess 15 coact in positioning the jaws properly upon the particular boring tool which is being gripped. The longitudinal grooves at the inner side of each jaw extend to the extreme forward end of the jaws so that not only will the larger sized jaws be properly centered, but the smaller sized jaws may be efiectively gripped. In Fig. 11, representing the jaws as contracted to their utmost, the small rectangular opening in the center indicates approximately the smallest drill that can be gripped. Since drills of smaller sizes cannot be effectively employed with hand-operated chucks, and since drills of larger sizes than indicated in dotted lines in Fig. 9 cannot be effectively driven by hand power, it follows that this chuck is universal, so far as concerns its capacity to receive and properly hold bits and drills to be driven by hand. The clamping action being effected by the forcing of the jaws outwardly, it follows that the location of the anti-friction bearing 9 is important and valuable in that heavy pressure may be brought to bear upon the tools with the exercise of but very little exertion in the turning of the operating sleeve.

What I claim is:

1. In a chuck, two companion jaws, operating means for moving said jaws toward and from each other, each of said jaws having a main groove extending longitudinally thereof, said grooves being arranged to face each other, said grooves being deepest at a point nearer to the forward than to the rear ends of said jaws, supplemental longitudinal excavations in each of said jaws at each side of each main groove, said supplemental longitudinal excavations extending to the rear of the deepest part of the main grooves.

2. In a chuck, two companion jaws, oper ating means for moving said jaws toward and from each other, each of said jaws having a main groove extending longitudinally thereof, said grooves being arranged to face each other, said grooves being deepest at a point nearer to the forward than to the rear ends of said jaws, supplemental longitudinal excavations in each of said jaws at each side of each main groove, said supplemental longitudinal excavations extending to the rear of the deepest part of the main grooves, the operating means for said jaws comprising a jaw holder having a converging tapered outlet in which said jaws stand and may slide, a driver block at the rear of said jaws, the forward part of said driver block being notched to form forwardly flaring bearing walls for the rear ends of the jaws and means for moving said block to and fro.

3. A chuck jaw of elongated form having therein a main longitudinal groove, said groove being deepened at a point intermediate its length and said groove being of angular cross section, said jaw having a supplemental excavation on each side of the main groove, both of said supplemental excavations extending rearwardly from said deepened part of said main groove.

JOHN S. FRAY. WVitnesses:

MARY L. DIMoND, CATHERINE A. SMITH. 

